Micrometer.



D. PETERS.

MIOROMETER.

APPLICATION FILED MAR. 16, 1909.

946,268. Patnted Jan. 11,1910.

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ATTORNEY.

UNITED STATES ATEN F TE.

DAVID PETERS, 0F JERSEY CITY, NEW JERSEY.

MICROMETER.

Specification of Letters Patent.

Patented J an. 11, 1910.

To all whom it may concern:

Be it known that 1, DAVID PETERS, a citizen of the United States,residing at Jersey City, New Jersey, have invented certain Improvementsin Micrometers, of which the following is a specification.

This invention relates more particularly to the reading of micrometerscrews, and the objects of the invention are to avoid in such readingthe necessity for any addition of various numbers or readings; to thusrender reading of the micrometer easier and quicker; to lessen theliability of making errors in reading a micrometer, and to obtain otheradvantages and results as may be brought out in the followingdescription.

Referring to the accompanying drawings, in which like numerals ofreference indicate corresponding parts in each of the several figures,Figure 1 is a side view of a micrometer of my improved constructionshowing a reading of seven hundred and ninety nine thousandths, and Fig.2 is a similar View showing a reading of eight hundred and onethousandths; Fig. 3 is a side view of the portion of the micrometer asshown in Fig. 2, with the barrel developed or spread out flat.

In said drawings, 101 indicates the U- shaped body of the micrometer,having a sleeve 102 in which the usual micrometer screw 103 works towardand away from an anvil 104 on the body. On the said sleeve 102 is alongitudinal line 105, across which are marked graduations, the smallestof which are each twenty-five thousandths and every fourth one beingnumbered, so that the series of figures on said sleeve from 1 to 10indicate each one-hundred thousandths. Upon the said sleeve 102 is abarrel 106 which rotates to turn the micrometer screw 103 as is usual.It is in certain novel features of this barrel 106, next to bedescribed, that the present invention more particularly inheres.

The barrel 106 is provided at its end which incloses the sleeve 102,with a circumferential series of longitudinal lines or graduations, eachone representing one thousandth. There are twenty-five of these linesaround the barrel 106, and thus any one of them in the course of acomplete revolution of the barrel travels longitudinally of the sleeve102 the distance of one of the smallest graduated divisions thereon. Oneof these longitudinal lines on the barrel, the one which should coincidewith the longitudinal line 105 on the sleeve at a reading of an evennumber of hundreds of thousandths, as 107 in the drawings, is selectedas the starting point for a spiral column 111 which extends four timesaround the barrel 106 and thus provides a series of spaces to receivenumbers from 1 up to 100, as shown.

The end of the barrel 106 which overlaps on the sleeve 102 is shaped ona spiral, as at 108, the ends of said spiral being on the zero line 107of the barrel, so that at said zero line a step 109 is formed. This stepis so located and of such length that when the zero line 107 on thebarrel 106 coincides with the longitudinal line 105 of the sleeve, thehigh part of the step or extremity of the reading line lies between theends of a subdivision of the sleeve, and the'low part is between theends of the next covered subdivision. Thus in turning the barrel, theextremity of the reading line at any time lies intermediate the ends ofa subdivision and never on the dividing lines of said subdivisions,changing suddenly from one subdivision to the next wherever the zeroline 107 of the barrel crosses the line 105 of the sleeve. The number ofthe subdivision of the larger divisions of the graduation on the sleeve102 in which the longitudinal reading line of the barrel 106 terminatesat the end of the barrel indicates the number of the transverse columnof the barrel 106 from which the tens and units of thousandths are to beread. Such tens and units can be read at a glance, and by prefixingthereto the figure of the last visible hundreds of thousandths line onthe sleeve102, a complete reading is had. For example, in Fig. 1 thelongitudinal line 112 of the barrel coincides with the line 105 of thesleeve and therefore is the reading line. The end of this lineterminates at the extremity of the barrel in the fourth subdivision ofthe seventh division on the sleeve. Hence we take with the figure seventhe number which is in the fourth spiral column of the barrel, nextabove the reading line 109, which is ninetynine, and so have at once thereading seven hundred and ninety nine. Again, in Fig. 2 the longitudinalline 110 of the barrel is the reading line, and the end of this line atthe extremity of the barrel lies in the first subdivision beyond theeighth division on the sleeve 102. We therefore read from the firstspiral column the unit one, which with the eight hundreds on the barrelmakes the whole reading eight hundred and one.

Obviously the numbers in the spiral columns, instead of being stampeddirectly above the longitudinal reading line of the barrel as shown,could be stamped on or across said lines, or the lines broken to receivesaid numbers, as is common in marking rules and the like.

It will be understood that the sleeve 102 is fast to the body 101 of themicrometer and that the screw 103 works therein as usual in micrometers.The barrel 106 is fast to the screw 103, enabling said screw to beturned, and said barrel partially telescopes the sleeve 102, all as isalso common and wellknown in micrometers.

Having thus described the invention, what I claim is:

1. In a micrometer, the combination with a sleeve having a longitudinalline and a series of divisions and subdivisions along said line, of abarrel partially telescoping said sleeve, said barrel havinglongitudinal lines forming as many graduations of its circumference asmake one of said subdivisions on the sleeve and a spiral line cuttingsaid longitudinal lines into as many columns as there are subdivisionsin one of said divisions on the sleeve, the divisions on the sleevebeing numbered consecutively and said graduations on the barrel beingnumbered consecutively through the spiral columns as part of one of thesaid divisions,

the said longitudinal lines of the barrel extending to the extremity ofthat end of the barrel inclosing the sleeve and adapted thereat to bebrought into coincidence with said longitudinal line of said sleeve.

2. In a micrometer, the combination with a sleeve having a series oflongitudinal divisions and subdivisions, of a barrel on said sleevehaving a series of circumferential graduations divided into as manyspiral columns as there are subdivisions in one of the said divisions onthe sleeve, each column containing as many graduations as make one ofthe said subdivisions, the divisions on the sleeve being numberedconsecutively and said graduations on the barrel being numberedconsecutively through the spiral columns as parts of one of saiddivisions, the extremity of said barrel inclosing said sleeve beingformed on a spiral whose ends terminate in the zero line of saidcircumferential graduations of the barrel.

8. The combination with a micrometer screw, of a sleeve having a seriesof longitudinal graduations, and a barrel on said sleeve having a seriesof circumferential. graduations, the extremity of said barrel iiiclosingsaid sleeve being formed on a spiral whose ends terminate in the zeroline of said circumferential graduations of the barrel.

DAVID PETERS.

In the presence of CHAS. P. DAY, RUssELL M. EVERETT.

